import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class BurritoInventoryServlet extends HttpServlet {
// How many "servings" of each item do we have?
private int cheese = 0;
private int rice = 0;
private int beans = 0;
private int chicken = 0;
// Add to the inventory as more servings are prepared.
public void addCheese(int added) { cheese += added; }
public void addRice(int added) { rice += added; }
public void addBeans(int added) { beans += added; }
public void addChicken(int added) { chicken += added; }
// Called when it's time to make a burrito.
// Returns true if there are enough ingredients to make the burrito,
// false if not. Decrements the ingredient count when there are enough.
synchronized public boolean makeBurrito() {
// Burritos require one serving of each item
if (cheese > 0 && rice > 0 && beans > 0 && chicken > 0) {
cheese--; rice--; beans--; chicken--;
return true; // can make the burrito
}
else {
// Could order more ingredients
return false; // cannot make the burrito
}
}
// Display the current inventory count.
public void doGet(HttpServletRequest req, HttpServletResponse res)
throws ServletException, IOException {
res.setContentType("text/html");
PrintWriter out = res.getWriter();
out.println("<HTML><HEAD><TITLE>Current Ingredients</TITLE></HEAD>");
out.println("<BODY>");
out.println("<TABLE BORDER=1>");
out.println("<TR><TH COLSPAN=2>Current ingredients:</TH></TR>");
out.println("<TR><TD>Cheese:</TD><TD>" + cheese + "</TD></TR>");
out.println("<TR><TD>Rice:</TD><TD>" + rice + "</TD></TR>");
out.println("<TR><TD>Beans:</TD><TD>" + beans + "</TD></TR>");
out.println("<TR><TD>Chicken:</TD><TD>" + chicken + "</TD></TR>");
out.println("</TABLE>");
out.println("</BODY></HTML>");
}
// Load the stored inventory count
public void init(ServletConfig config) throws ServletException {
super.init(config);
loadState();
}
public void loadState() {
// Try to load the counts
FileInputStream file = null;
try {
file = new FileInputStream("BurritoInventoryServlet.state");
DataInputStream in = new DataInputStream(file);
cheese = in.readInt();
rice = in.readInt();
beans = in.readInt();
chicken = in.readInt();
file.close();
return;
}
catch (IOException ignored) {
// Problem during read
}
finally {
try { if (file != null) file.close(); }
catch (IOException ignored) { }
}
}
public void destroy() {
saveState();
}
public void saveState() {
// Try to save the counts
FileOutputStream file = null;
try {
file = new FileOutputStream("BurritoInventoryServlet.state");
DataOutputStream out = new DataOutputStream(file);
out.writeInt(cheese);
out.writeInt(rice);
out.writeInt(beans);
out.writeInt(chicken);
return;
}
catch (IOException ignored) {
// Problem during write
}
finally {
try { if (file != null) file.close(); }
catch (IOException ignored) { }
}
}
}
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